From DE 43 20 288, for example, a torque converter is known, in which fresh oil can be supplied to the converter torus, e.g., to the impeller, via a supply line. The heated oil can be removed, for example, in the area of the casing cover, which has openings in the form of radial channels, through which a flow connection can be established between the converter torus and a withdrawal line. The channels are created by providing the converter cover, on its side facing the turbine hub, with projections located at predetermineable distances to one another in the circumferential direction. These projections serve as contact points for a disk; the disk interacts with the casing cover and forms, when secured to the projections, a channel between each respective pair of projections.
To form such channels, the torque converter of DE 43 20 288 requires two components, i.e., the casing cover and the disk. For this reason, manufacturing the openings entails relatively high technical production costs, especially when the two components are connected to one another by welding and heat-related distortion must thus be expected. Because of this, it is possible for leakage to result in an otherwise pressure-tight arrangement of the disk relative to the turbine hub, which can be corrected only by expensive reworking.
Japanese laid-open publication 2-245 562 discloses a torque converter including a pressure fluid passage for activating the piston of a bridge coupling or lock-up clutch. It fails to disclose the unitary construction of a casing cover and a relatively thin separating wall which at the same time serves to prevent the axial movement of the turbine hub on one side of the passage. The reference also fails to disclose any means for centering the converter hub on the casing cover which permits the assembly thereof without centering tools.
German laid-open publication DE-OS 41 17 151 A1 discloses a torque converter having a flow passage for cooling the converter fluid from the outside of the casing cover into a conduit in the output shaft. A flow passage between the converter hub a part of the casing cover serving simultaneously as axial support for the turbine hub is not disclosed.